2006 Toyota Noah 1AZ - Revs

I have a Toyota Noah 2006 Engine 1AZ, starts to act really weird!!.. it lost the REV, even if I depress the pedal nothing happened but engine idle is fine…! Then I have to turn the engine off and restart and worked ok. I have noticed this happened whenever I travel long route, that’s mean when the car got heat.
The car temperature if fine.
Need your help please!??

The reason of putting Previa in model because my model Does not exist.!!
my car as stated above is Toyota Noah 2006 1AZ

It doesn’t exist in The US, where this site is based, and where at least 99% of the forum’s members reside. However, one thing is universal, and that is the need to have the vehicle’s stored trouble codes “read” in order to help with a diagnosis.

In the US, many/most auto parts stores will “read” those trouble codes free of charge.
I have no idea whether this policy exists with auto parts stores in your unknown country, but a few phone calls might help you to find out whether there are any auto parts stores that will plug-in a code reader for you, without a fee.

If you are able to get the stored codes, then you can come back to this thread to post them for more specific advice.


You car probably has a drive-by-wire throttle system. That means that unlike most 20th century cars where stepping on the pedal cause a cable or rod to directly move the throttle valve, with yours there’s no physical connection between the accel pedal and the throttle valve. It’s done instead by the engine computer electrically sensing the accel pedal angle, and then commanding an electrical actuator on the throttle body to open the throttle valve. So something’s wrong with all that, most likely either the pedal angle sensor or the actuator.

Does this seem overly complicated to you? I mean all that’s necessary is to move the throttle valve. I think the reason the car designers are using this system is b/c there’s a variety of things that must increase the idle rpm to avoid the engine stalling; i.e. low coolant temperature, turning on the headlights, turning the steering wheel, etc etc. So instead of requiring a separate mechanism for each of those, they decided to just deal with it once and for all by using the computer & an electrical actuator to adjust the idle speed as required.

That seems clear, I’ll try to clean the throttle first and see if will do then will proceed to change the actuator.
Thanks I’ll let you know what happened.

You will likely waste money changing parts without a proper diagnosis.
Hopefully near where you live there is an experienced mechanic (perhaps at the dealer?) who can do some testing before throwing parts at the problem.

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